Now, they present new leads on how the human brain has evolved, and a starting point for studying neurological diseases. For example, the sequence of DPP10a gene critically important for normal human brain developmentnot only showed distinct human-specific chromatin structures different from other primate brains such as the chimpanzee or the macaque, but the underlying DNA sequence showed some interesting differences from two extinct primatesthe Neanderthal and Denisovan, most closely related to our own species and also referred to as 'archaic hominins'.
"Many neurological disorders are unique to human and are very hard as a clinical syndrome to study in animals, such as Alzheimer's disease, autism, and depression," said Dr. Akbarian. "By studying epigenetics we can learn more about those unique pieces of the human genome."
The research team also discovered that several of these chromatin regions appear to physically interact with each other inside the cell nucleus, despite being separated by hundreds of thousands of DNA strands on the genome. This phenomenon of "chromatin looping" appears to control the expression of neighboring genes, including several with a critical role for human brain development.
"There is growing consensus among genome researchers that much of what was previously considered as 'junk sequences' in our genomes indeed could play some sort of regulatory role," said Dr. Akbarian.
This study was supported by grants from the National Institutes of Health. Dr. Akbarian plans to do more epigenetic studies in other areas of the brain to see if there are additional chromatin regions that are unique to humans. They also plan to study the epigenomes of other mammals with highly evolved social behaviors such as elephants.
Dr. Akbarian joined Mount Sinai in July 2012. He is internationally known for his cutting-edge research on the epigenetic mechani
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